Electrolytic activation of fluids

ABSTRACT

A unipolar liquid activation apparatus with an anode cell ( 40 ), a cathode cell ( 41 ), and a direct current power supply ( 43 ), the anode cell having an anode ( 46 ), a liquid inlet ( 50 ) and an anolyte outlet ( 51 ), the cathode cell having a cathode ( 47 ), a liquid inlet ( 52 ) and a catholyte outlet ( 53 ), means to electrically connect the anode and cathode respectively to the direct current power supply. The cells can also include connected solution electrodes ( 44, 49 ). Alternatively the anode and cathode can be compound electrodes ( 81, 83 ) with means to electrically connect the inner anode electrode and the inner cathode electrode. The anode cell and cathode cell may be adjacent to each other and electrically connected by an electronic membrane ( 104 ) in contact respectively with the anode and cathode and allowing flow of electrons only from the cathode to the anode. The unipolar activation apparatus may also be an anode ( 141 ) and a cathode ( 142 ) electrically isolated from each other but connected to a DC power source.

FIELD OF INVENTION

This invention concerns apparatus and process to carry out electrolyticunipolar activation of fluids also known as unbalanced electrolysis.

BACKGROUND AND PRIOR ART

In a conventional electrolytic reaction in a conventional diaphragmcell, electrons are removed from the anode electrode resulting in anoxidation reaction at the anode cell. The ions produced at the anodeelectrode migrate through the diaphragm to the cathode electrode due todifference in concentration of ions. The ions are reduced at the cathodecompleting the ionic circuit of the diaphragm cell. The slow movement ofions is often sped up by transferring the anolyte from the anode cell tothe cathode cell. The complete electronic circuit of the diaphragm cellis shown on FIG. 1.

FIG. 1 is a conventional diaphragm electrolytic cell where a DC source 1is connected to the anode electrode 2 and cathode electrode 3 with adiaphragm 4 separating the anode cell 7 and anode electrode 2 from thecathode cell 8 and cathode electrode 3. The complete electronic circuitpasses from the anode electrode 2 to the DC source 1 to the cathodeelectrode 3 through the catholyte 5 through the diaphragm 4 through theanolyte 6 and to the anode electrode 2.

The activation of liquids by subjecting the liquid to unipolaractivation or unbalanced electrolysis is becoming a major branch ofchemistry. The subject has been studied extensively in Russia and someof the studies have been published by Dr. Vitold Bakhir in severalpapers. Dr. Bakhir, et al have been granted U.S. Pat. No. 5,427,667(Jun. 27, 1995) for an apparatus for the electrochemical treatment ofwater, with the objective of sterilizing the water or using the productas a disinfectant. Dr. Bakhir's apparatus is tubular in shape and isdiagrammatically shown in FIG. 2.

FIG. 2 is a diagram of a tubular diaphragm cell described in Dr.Bakhir's U.S. Pat. No. 5,427,667. The outer tube 10 is cathode electrodeand the inner tube 11 is the anode electrode and these are separated bya cylindrical ceramic diaphragm 12. The DC power source is not shown butis connected to the anode electrode and the cathode electrode. Liquid 13to be activated is fed into the outer cell and exits as activatedcatholyte 14. Further liquid 15 to be activated is fed into the innercell and exits as activated anolyte 16. Alternatively the outer tube maybe the cathode electrode and the inner tube may be the anode electrode.The electrodes are, as discussed in relation to the simpleelectrochemical cell above, separated by a ion permeable diaphragm.Liquid is fed into the outer tube and is discharged as the catholyte anda separate liquid is fed into the inner tube and is discharged as theanolyte. There is no mixing of the liquids and the apparatus acts toremove electrons from the anolyte and add electrons to the catholyte.

While the major application of Dr. Bakhir's apparatus is the treatmentof water, the application of unbalanced electrochemical activation isvery extensive as described in the papers of Dr. Bakhir. The benefits ofunipolar activation can be examined in almost every commercialapplication in energy, health, agriculture, environment, and generalindustries. The only limitation in most cases is the use of a diaphragmbetween the anode and cathode electrodes that limit reaction rates dueto the impedance of the diaphragm and problems from blockage of thediaphragm from solids and salt formation.

Our company has been granted Australian patents 654774 (Mar. 29, 1993),707701 (Oct. 28, 1999) and U.S. Pat. No. 5,569,370 (Oct. 29, 1996), U.S.Pat. No. 5,882,502 (Mar. 16, 1999) regarding an electrolytic cell thatdoes not use a diaphragm or membrane between the anode and the cathodeelectrodes. This electrolytic cell has a very high Faraday efficiency, ahigher energy efficiency and faster reaction rate than conventionaldiaphragm cells allowing this electrolytic cell to be used in commercialapplications particularly where the use of a diaphragm is a disadvantagebecause of blockage of the diaphragm from solid particles, deposits ofsalts or oily electrolytes. This is illustrated in FIG. 3.

FIG. 3 shows the electrolytic system covered in U.S. Pat. No. 5,882,502where electrolysis is carried out without a diaphragm between the anodeelectrode and the cathode electrode. The anode cell 20 is separate fromthe cathode cell 21. The complete electronic circuit starts from theanode electrode 22 to the DC power source 23 to the cathode electrode 24through the catholyte 25 to the cathode solution electrode 26 to theanode solution electrode 27 through the anolyte 28 and to the anodeelectrode 22. Ions produced at the anode cell in the anolyte aretransferred 29 with the anolyte to the cathode cell and the reducedcatholyte is returned 19 to the anode cell to provide the ionic circuitof the system.

DESCRIPTION OF THE INVENTION

Unipolar activation involves only the transfer of electrons from theanode to the cathode electrodes and there is no ionic circuit as inconventional electrolytic reactions. However, there is usually acomplete electronic circuit between the anode electrode, the DC powersource, and the cathode electrode. Part of this invention is anapparatus where unipolar activation is carried out without a completeelectronic circuit. The unipolar activation system must also accommodatefeatures such as high reaction rates, energy effiency, pressure,temperature, mixtures of liquids, liquids and gases, or liquids andsolids required for commercial applications. These features are bestaccommodated in electrolytic systems where the anode cell is separatefrom the cathode cell and with the absence of a diaphragm.

In one form therefore the invention is said to reside in a unipolarliquid activation apparatus including an anode cell, a cathode cell, anda direct current power supply, the anode cell having an anode, a liquidinlet and an anolyte outlet, the cathode cell having an cathode, aliquid inlet and a catholyte outlet, means to electrically connect theanode and cathode respectively to the direct current power supply, meansto supply fluid to the anode and cathode cells, and means to recover theactivated anolyte from the anode cell and the activated catholyte fromthe cathode cell.

In one embodiment the anode cell further includes a first solutionelectrode and the cathode cell includes a second solution electrode andfurther including means to electrically connect the first solutionelectrode and the second solution electrode.

In an alternative embodiment the anode is a compound anode, the compoundanode having an inner anode electrode and an outer electrode being theanode and separated by and in intimate contact with an electrolyticmembrane or internal electrolyte, the cathode is a compound cathode, thecompound cathode having an inner cathode electrode and a outer electrodebeing the cathode and separated by and in intimate contact with anelectrolytic membrane or internal electrolyte and means to electricallyconnect the inner anode electrode to the inner cathode electrode.

Alternatively the anode cell and cathode cell are adjacent to each otherand the first and second solution electrodes and the means toelectrically connect the first solution electrode and the secondsolution electrode together comprise a common first and second solutionelectrode being an electronic membrane in contact respectively with theanode and cathode and allowing flow of electrons only from the cathodeto the anode.

The electrical resistance of the electronic membrane in contact with theanode and cathode electrode may be very high resulting in the anodeelectrode being electrically isolated from the cathode electrode.

Preferably the anode electrode and the cathode electrode are cylindricalincorporating internal surface enhancement features such as gauze orexpanded metal connected to the electrodes.

Preferably the positive terminal of the DC power source is connected tothe anode electrode and the negative positive terminal of the DC powersource is connected to the cathode electrode and the ends of the anodeand cathode electrodes may be connected to electrically non-conductinginlet and outlet.

The means to supply fluid to the anode and cathode cells may includesmeans to feed at least one of a liquid, a gas or a solid or a mixturethereof.

The means to electrically connect the first solution electrode and thesecond solution electrode is a wire between the respective cells.

Preferably the cathode and anode have a high surface area to increasethe contact area with the respective liquids.

In an alternative form the invention is said to reside in a method ofsterilisation of liquid including the step of passing streams of theliquid through respective electrolytic cells, the electrolytic cellsbeing an anode cell having an anode, a liquid inlet and an anolyteoutlet and a cathode cell having an cathode, a liquid inlet and acatholyte outlet, a direct current power supply electrically connectedto the anode and cathode respectively,

-   means to supply liquid to the anode and cathode cells, and-   means to recover the activated anolyte from the anode cell and the    activated catholyte from the cathode cell.

Hence it will be seen that the apparatus performs its function ofremoving electrons from fluid at the anode and adding electrons to thefluid in the cathode without the use of a diaphragm or membrane incontact with the fluids when a direct current power is applied to theanode and cathode electrodes. The absence of a diaphragm allows fastreaction rate that is required for commercial applications. The otherunipolar activation apparatus removes electrons from the anode solutionand adds electrons to the cathode solution from a DC power source but inthis apparatus, the anode solution is completely electrically separatefrom the cathode solution. The invention has important commercialapplications in energy, environment, agriculture, health, chemical andgeneral industries.

The invention may have three separate embodiments of electrochemicalsystems that may be used in commercial applications of unipolaractivation. Two involve unipolar activation where there is a completeelectronic circuit while the third apparatus does not have a completeelectronic circuit. These apparatus may be used for unipolar activationof single liquids such as water, mixtures of liquids, liquid and gas, orliquid and solids.

This then generally describes the invention but to assist withunderstanding reference will now be made to the accompanying drawingsand examples.

In the drawings:

FIG. 1 shows a prior art a conventional diaphragm electrolytic cell;

FIG. 2 shows a diagram of a prior art tubular diaphragm cell describedin Dr. Bakhir's U.S. Pat. No. 5,427,667;

FIG. 3 shows a prior art electrolytic system covered in U.S. Pat. No.5,882,502;

FIG. 4 shows a first embodiment of the invention being anelectrochemical system for unipolar activation;

FIG. 5 shows a second embodiment of the invention as an experimentalapparatus built to examine the unipolar activation of water for use asdisinfectant in cooling tower water;

FIG. 6 shows a further embodiment of the invention of an electrochemicalsystem for unipolar activation using a compound electrode system;

FIG. 7 shows a further embodiment of the invention of an electrochemicalsystem for unipolar activation;

FIG. 8 shows a further embodiment of the invention of an electrochemicalsystem for unipolar activation with the anode electrically isolated fromthe cathode; and

FIG. 9 shows a diagram of a commercial unit following the principlesshown in FIG. 8.

DESCRIPTION OF PREFERRED EMBODIMENTS AND THE DRAWINGS

FIG. 4 is a diagram showing an electrolytic system for unipolaractivation of fluids with a solution electrode adjacent to each of theanode electrode and cathode electrode. The function of this system is toremove electrons from the fluid in the anode cell and to add electronsto the fluid in the cathode cell. The anode cell 40 is separate from thecathode cell 41. The complete electronic circuit starts from the anodeelectrode 46 to the DC power source 43 to the cathode electrode 47through the catholyte 48 to the cathode solution electrode 49 via theelectrical link 56 to the anode solution electrode 44 through theanolyte 45 and to the anode electrode 46. There is no transfer of ionsbetween the anode cell and the cathode cell. Liquid 50 is fed to theanode cell and is discharged as activated anolyte 51. Liquid 52 is fedto the cathode cell and is discharged as activated catholyte 53. Desiredchemical reactions may be achieved by the system shown on FIG. 4 byadding chemicals, gas, another liquid, or fine solids 54 to the anodecell or 55 to the cathode cell. For instance, the production of hydrogenperoxide in the activation of water may be increased by adding oxygen tothe cathode.

FIG. 5 is a diagram of a large laboratory apparatus to carry out wateractivation. The anode circuit is separate from the cathode circuitexcept for the connection with the DC power source 70 and the solutionelectrodes. The anode liquid is circulated from a heated anode pump box60 by a variable speed pump 61 to a temperature controlled heater 62 toa 50 mm diameter×228 mm long titanium tube anode 63 with a 25 mmdiameter×368 mm long titanium tube anode solution electrode 64 and thenreturned to the heated anode pump box 60. The cathode liquid iscirculated from a heated cathode pump box 65 by a variable speed pump 66to a temperature controlled heater 67 to a 50 mm diameter×228 longtitanium tube cathode 68 with a 38 mm diameter×368 mm long titanium tubecathode solution electrode 69 and then returned to the heated cathodepump box 65. The positive terminal of the DC power source 70 isconnected to the anode electrode 63 and the negative terminal isconnected to the cathode electrode 68. The anode solution electrode 64is connected to the cathode solution electrode 69 by electrical link 71.The pH of the anode liquid and the cathode liquid were measuredregularly by a calibrated EUTECH pH FM1 pH meter. Liquids may beactivated at different liquid composition, different voltage andcurrent, and different activation periods.

FIG. 6 is a diagram of a system for carrying out unipolar activationusing compound electrodes. The anode compound electrode 81 is located inthe anode cell 80 and the cathode compound electrode 83 is located inthe cathode cell 82. The anode compound electrode 81 consists of anouter anode electrode 84 that is in contact with the anolyte 87 and aninner anode electrode 85 in contact with the outer anode electrode 84through an internal solution or gel or electronic membrane 86 thatallows current to flow from the internal anode electrode 85 to the outeranode electrode 84. The cathode compound electrode 83 consists of anouter cathode electrode 88 that is in contact with the catholyte 91 andan inner cathode electrode 89 in contact with the outer cathodeelectrode through an internal solution or gel or electronic membrane 90that allows current to flow from the outer cathode electrode 88 to theinner cathode electrode 89. The positive terminal of the DC power source92 is connected to the outer anode electrode 84 while the negativeterminal is connected to the outer cathode electrode 88. The innercathode electrode 89 is connected to the inner anode electrode 85 by anelectrical link 99. Liquid 93 is fed to the anode cell 80 and exits theanode cell as activated anolyte 94. Liquid 95 is fed into the cathodecell 82 and is discharged as activated catholyte 96. Other chemicalssuch as liquids, gases, or fine solids 97 may be fed into the anode cellor 98 to the cathode cell to achieve desired reactions.

FIG. 7 is a diagram showing an electrolytic cell with the anodeelectrode and the cathode electrode having a common wall. The anode cell100 has a common wall 101 with the cathode cell 102. The anode electrode103 is located in the anode cell in contact with the anolyte 108 andconnected electrically to the cathode electrode 105 by an electrolyticmembrane or internal electrolyte or gel or ceramic conductor 104. Thecathode electrode is in contact with the catholyte 107. The positiveterminal of the DC power source 106 is connected to the anode electrode103 while the negative terminal is connected to the cathode electrode105. Liquid 109 is fed to the anode cell 100 and is discharged asactivated anolyte 110. Liquid 111 is fed to the cathode cell 102 and isdischarged as activated catholyte 112. In this embodiment theelectrolytic membrane or internal electrolyte or gel or ceramicconductor 104 acts as the respective solution electrodes and electricallink of the earlier embodiments.

The unipolar apparatus in FIG. 8 is similar in principle to theapparatus shown on FIG. 7 if the electrical resistance of the membrane104 is increased to infinity. The result is that the anode electrode andthe cathode electrodes are electrically isolated from each other. InFIG. 8, the anode cell 120 consists of the outer anode cell 121 of 50 mmdiameter×228 mm long titanium tube internally coated with platinum,ruthenium and rhodium and a further anode electrode 122 of 38 mmdiameter titanium tube coated with platinum ruthenium and rhodium bothconnected to the positive of the DC power source 123. The cathode cell124 consists of the outer cathode cell 125 of 50 mm diameter×228 mm longtitanium tube internally coated with platinum, ruthenium and rhodium andfurther cathode electrode 126 of 38 mm diameter titanium tube coatedwith platinum ruthenium and rhodium both connected to the negative ofthe DC power source 123. Variable speed pump 127 circulates the anodeliquid through heater 128 through anode electrode 120 and anode pump box129. Variable speed pump 130 circulates the cathode liquid throughheater 131, through cathode cell 124 and cathode pump box 132. Not shownis EUTECH pH FM1 pH meter to measure the pH regularly. The apparatusshown on FIG. 8 was used to obtain the data in Table 4 below.

FIG. 9 is a diagram of a commercial unit following the principle shownin FIG. 8 where the anode electrode is electrically isolated from thecathode electrode. The anode electrode 141 is a tube or a pipe made of aconducting material and incorporate surface increasing features such asgauze or expanded metal connected to the tube electrode not only toincrease the surface area of the electrode but also to ensure intimatecontact between the fluid and the electrode. The internal surface of theelectrode may be coated with a material for corrosion protection as wellas reduction of electrode over-voltage. The cathode electrode is 142 issimilarly constructed. Where high voltage is applied, the outer surfacesof the anode and cathode electrodes may be covered with an electricalinsulation. The anode electrode is connected to the positive of the DCpower source 140 and the negative of the DC power source 140 isconnected to the cathode electrode. The ends of the anode and cathodeelectrodes are connected to electrically non-conducting pieces 143.

Experimental Results

As discussed above FIG. 5 is an experimental apparatus built to examinethe unipolar activation of water for use as disinfectant in coolingtower water to control legionella bacteria and sterilizing all waterused in hospitals to help control bacteria that have become resistant toantibiotics. The DC power source 70 has an 18 volts DC-20 amperescapacity. The anode electrode 63 is a 50-millimetre (mm) diameter×228-mmlong titanium tube internally coated with platinum, ruthenium andrhodium and the anode solution electrode 64 is 25-mm diameter titaniumtube coated externally with platinum, ruthenium, and rhodium. Thecathode electrode 68 is a 50-mm diameter×228-mm long titanium tubeinternally coated with platinum, ruthenium and rhodium and the cathodesolution electrode 69 is 38-mm diameter titanium tube coated externallywith platinum, ruthenium, and rhodium. The apparatus is fitted withvariable speed circulating pumps, pressure gauges, heaters controlled bytemperature indicating controllers with liquid pH at the cathode andanode measured regularly by a EUTECH pH FM1 pH meter calibrated beforeeach run to 7.01, 10.01, and 4.01 pH standard solutions. Voltage betweenthe anode electrode and the anode solution electrode (anode voltage) andthe cathode solution electrode and the cathode electrode (cathodevoltage) were measured regularly. Adelaide tap water at room temperaturewas used for the water sterilization test while Adelaide tap water at 50degrees Celsius with a minute amount of sodium chloride to simulatecommercial conditions, were used in the cooling water disinfection test.The anode and cathode circuits each accommodated 5 litres of liquid.Adelaide tap water would contain very minute amounts of chlorine, iron,calcium and aluminium sulfates. The experimental results were: TABLE 1Disinfection of Water for a Cooling Tower (Temperature 50 C.) AdelaideTap Water with 3 grams per liter of sodium chloride Cell Voltage 9.0 9.09.0 9.0 9.0 9.0 Cell Amperes 0.63 0.66 0.69 0.65 0.73 0.67 Time(minutes) 0 60 120 180 270 556 Anode Voltage 3.38 2.83 2.84 2.79 2.852.85 Cathode Voltage 5.64 6.12 6.18 6.22 6.15 6.17 Anode Liquid pH 7.76.8 6.5 6.4 6.1 4.3 Cathode Liquid pH 8.1 8.1 8.0 8.0 7.9 7.9

The pH of Adelaide tap water with the sodium chloride is 7.0 to 7.1measured before being charged into the apparatus. The pH of the liquidchanged while it was being heated in the apparatus. A voltage of 0.453volts was detected between the anode and the cathode electrode duringheating up and this may explain the change in the pH of the water beforeDC power was applied to the electrodes. Nevertheless, if the starting pHof the liquid was 7.1, the anode liquid became acidic while the cathodeliquid became alkaline. The results conform to the published data of Dr.Bakhir that the anolyte became acidic (pH range of 0.025 to 7) while thecatholyte became alkaline (pH range of 7.50 to 13.0). Test are now inprogress to test the effect of the catholyte and anolyte from thisexperiment on legionella bacteria. TABLE 2 Sterilization Test onAdelaide Tap Water (Temperature 25 to 26 C.) Time 0 360 minutes CellVoltage 18.0 18.0 Cell Amperes 0.20 0.26 Anode Voltage 4.1 4.3 CathodeVoltage 13.9 13.7 Anode Liquid pH 6.9 6.0 Cathode Liquid pH 6.9 8.2

The anode liquid became acidic while the cathode liquid became alkaline.Although chemical analysis of the products was not carried out, the pHof the products from the anode and the cathode followed Dr. Bakhir'spublished data. The smell of the products also indicated the presence ofhydrogen peroxide.

Unipolar electrolytic activation may also be carried out using compoundelectrode as shown on FIG. 6. The feature of the compound electrode isthat only the anode electrode 81 and the cathode electrode 83 are incontact with the anode and cathode liquids respectively but a completeelectronic circuit is still achieved. The complete electronic flow isfrom the anode electrode 84 to the DC power source 92 to the cathodeelectrode 88 through the cathode electronic membrane or internalcatholyte 90 to the cathode internal electrode 89 to the anode internalelectrode 85 through the anode electronic membrane or internal anolyte86 to the anode electrode 84. The electronic membrane 86 at the anodeelectrode allows the flow of electrons from the anode internal electrodeto the anode electrode. At the cathode electrode, the electronicmembrane 90 allows the flow of electrons from the cathode electrode tothe cathode internal electrode. A preliminary experiment was carried outusing cubical electrodes made of 316 stainless steel. The anodeelectrode is 38.33 millimetres wide×88.96 millimetres long (inside) incross section×250 millimetres deep. The internal anode solutionelectrode is 29.31 mm wide×79.87 long to give a gap of about 4.5 mm. Thecathode electrode is 38.42 mm wide×88.7 mm long (inside) in crosssection×250 mm deep. The internal cathode solution electrode is 19.71 mmwide×69.38 mm long to give a gap of about 9.3 mm. A weak potassiumhydroxide solution with a pH of 13.7 was used as the internalelectrolyte for the anode and the cathode. Adelaide tap water was usedin the anode and cathode circuit. The anode and cathode circuitsaccommodated about 1.6 litres of liquid. Variable speed pumps were usedto circulate the Adelaide tap water through the electrodes. Thepreliminary test was carried out at room temperature and the externalanolyte and catholyte liquid pH were measured at regular intervals. TheDC power source was set to current control mode for the test. Electrodematerial and shape and internal anolyte and catholyte characteristicswere not optimized in this preliminary test. The results of the testwere: TABLE 3 Unipolar Activation of Adelaide Tap Water Using CompoundElectrodes Time (minutes) 0 2 60 120 180 240 Cell Voltage 3.26 3.10 3.263.34 3.62 3.57 Cell Amperes 0.03 0.01 0.01 0.01 0.05 0.05 Anode Voltage1.58 1.45 1.56 1.64 1.79 1.77 Cathode Volts 1.71 1.67 1.72 1.73 1.841.83 Anode pH 7.9 8.3 8.5 8.5 8.5 8.4 Cathode pH 7.9 8.3 8.5 8.6 8.6 8.6

The cell current was reduced from 0.03 to 0.01 amperes after the startof the experiment because bubbles were noted in both the anode andcathode internal electrodes indicating reaction was taking place in theinternal electrolyte. This is an area where more studies need to be madeto ensure that the internal electrolyte acted only as an electronconductor. The experimental results indicated that a chemical reactionoccurred within the anolyte and the catholyte and the differentreactions was indicated by the difference in the ending pH of theanolyte and catholyte.

The preliminary test indicated that the compound electrode is successfulin carrying out electrolytic unipolar activation of liquids. The modelthat would fit the results is that there is a complete electroniccircuit as described above. Since the anode electrode iselectro-positive, electrons are removed from the anolyte liquid at theanode cell. Electrons are transferred to the catholyte liquid by thenegative cathode electrode. The electrical resistance of the internalsolution or the electrolytic membrane is an important variable in theoperation of this compound electrode. For a given cell voltage, thehigher the electrical resistance of the membrane or internal solution,the more electrons are available at the anode electrode and cathodeelectrode for unipolar reactions.

A variation of the compound electrode is shown on FIG. 7 where thesolution electrode is eliminated and an internal solution or gel orelectronic membrane made from polymer or ceramic is in contact with boththe anode electrode and the cathode electrode to provide the completeelectronic circuit. The electronic membrane allows the flow of electronsfrom the cathode to the anode electrode only. The anode electrode andthe cathode electrode are separated by a common wall that is part of theanode cell and the cathode cell. In a commercial unit, the anode celland cathode cell may be cubical or cylindrical electrodes and containthe anolyte and catholyte respectively.

The third apparatus for carrying out unipolar activation was developedfrom the concept of the compound electrodes. If the resistance of theelectrolytic membrane or internal electrolyte were made very high suchas infinitely high, there will be no electron flow between the anode andcathode electrode via the electrical link. The electron flow will befrom the anode electrode to the DC power source and from the DC powersource to the cathode electrode. These electrons are used entirely inchemical reactions at the anode cell and in the chemical reactions atthe cathode cell. To test this concept, the apparatus shown on FIG. 5was arranged so that anode electrode and the anode solution electrodewere connected and acted as the anode electrode. The same connectionswere made of the cathode electrode and the cathode solution electrode asshown on FIG. 8. The anode electrode is a 50 mm×288 mm long titaniumtube coated with platinum, ruthenium and rhodium and the anode solutionelectrode connected to the anode electrode has an outside diameter of 38mm coated with platinum, ruthenium and rhodium. The cathode electrode isexactly the same as the anode electrode. Adelaide tap water was used asthe electrolyte and two tests were conducted, one at 9.02 volts and theother at 18.04 volts. The results are shown on Table 4. TABLE 4 UnipolarActivation Using Separate Electrodes Time, minutes 0 15 30 45 60 CellVoltage 9.02 9.02 9.02 9.02 9.02 Cell Amperes 0.00 0.00 0.00 0.00 0.00Anode Temp. C. 16 17 18 18 18 Cathode Temp C. 17 17 18 18 18 Anode pH6.7 6.7 7.0 6.8 7.0 Cathode pH 6.2 6.0 5.9 5.5 4.2 Cell Voltage 18.0418.04 18.04 18.04 18.04 Cell Amperes 0.00 0.00 0.00 0.00 0.00 AnodeTemp. C. 16 18 18 18 19 Cathode Temp. C. 17 18 18 18 19 Anode pH 6.9 6.97.1 7.2 7.2 Cathode pH 6.7 6.9 6.9 7.0 6.7

Effort to measure the current was not successful and the current wasbelow the 2 milli-ampere range of the instrument available. The resultsshow that the anode liquid increased in pH (alkaline) while the cathodeliquid decreased in pH (acidic). This trend is more pronounced at thelower voltage (9 volts) than at the higher voltage of 18 volts. Thetrend is also opposite to that shown on Table 1. The difference inunipolar action between Table 1 and Table 4 is that electrons passthrough the electrolyte in Table 1 similar to the apparatus of Dr.Bakhir while in Table 4, the electrons do not pass through theelectrolyte. The electrolyte was passed at turbulent action in theexperiments in Table 4 to ensure that there is no dead spot and that theelectrolyte was in good contact with the electrodes.

The results in Table 4 indicate that there may be a different regime ofreactions in this type of unipolar activation. There may be less pHactive species produced and more pH non-active species. The cell voltageand the nature of the fluids passing through the electrodes or theadditives in the fluids would affect the results desired.

In a commercial system, the most appropriate electrodes may be pipes ortubes with surface increasing features such as gauss, or expanded metal,or helical guides inside the electrode with surfaces coated withmaterial for corrosion resistance and low over-voltage characteristics.A diagram of such a commercial unit is shown on FIG. 9 where a DC source140 is connected to the cylindrical anode electrode 141 and cylindricalcathode electrode 142 with liquid fed to each electrode. Activatedanolyte is produced at the anode cell and activated catholyte isproduced at the cathode cell.

Throughout this specification various indications have been given as tothe scope of this invention but the invention is not limited to any oneof these but may reside in two or more of these combined together. Theexamples are given for illustration only and not for limitation.

Throughout this specification and the claims that follow unless thecontext requires otherwise, the words ‘comprise’ and ‘include’ andvariations such as ‘comprising’ and ‘including’ will be understood toimply the inclusion of a stated integer or group of integers but not theexclusion of any other integer or group of integers.

1. A unipolar liquid activation apparatus including an anode cell, acathode cell, and a direct current power supply, the anode cell havingan anode, a liquid inlet and an anolyte outlet, the cathode cell havingan cathode, a liquid inlet and a catholyte outlet, means to electricallyconnect the anode and cathode respectively to the direct current powersupply, means to supply fluid to the anode and cathode cells, and meansto recover the activated anolyte from the anode cell and the activatedcatholyte from the cathode cell.
 2. A unipolar liquid activationapparatus as in claim 1 wherein the anode cell further includes a firstsolution electrode and the cathode cell includes a second solutionelectrode and further including means to electrically connect the firstsolution electrode and the second solution electrode.
 3. A unipolarliquid activation apparatus as in claim 1 wherein the anode is acompound anode, the compound anode having an inner anode electrode andan outer electrode being the anode and separated by and in intimatecontact with an electrolytic membrane or internal electrolyte, thecathode is a compound cathode, the compound cathode having an innercathode electrode and a outer electrode being the cathode and separatedby and in intimate contact with an electrolytic membrane or internalelectrolyte and means to electrically connect the inner anode electrodeto the inner cathode electrode.
 4. A unipolar liquid activationapparatus as in claim 2 wherein the anode cell and cathode cell areadjacent to each other and the first and second solution electrodes andthe means to electrically connect the first solution electrode and thesecond solution electrode together comprise a common first and secondsolution electrode being an electronic membrane in contact respectivelywith the anode and cathode and allowing flow of electrons only from thecathode to the anode.
 5. A unipolar liquid activation apparatus as inclaim 4 wherein the electrical resistance of the electronic membrane incontact with the anode and cathode electrode is very high resulting inthe anode electrode being electrically isolated from the cathodeelectrode.
 6. A unipolar liquid activation apparatus as in claim 1wherein the anode electrode and the cathode electrode are cylindricalincorporating internal surface enhancement features such as gauze orexpanded metal connected to the electrodes.
 7. A unipolar liquidapparatus as in claim 6 wherein the positive terminal of the DC powersource is connected to the anode electrode and the negative positiveterminal of the DC power source is connected to the cathode electrode.8. A unipolar liquid apparatus as in claim 6 wherein the ends of theanode and cathode electrodes are connected to electricallynon-conducting inlet and outlet.
 9. A unipolar liquid apparatus as inclaims 1 wherein the means to supply fluid to the anode and cathodecells includes means to feed at least one of a liquid, a gas or a solidor a mixture thereof.
 10. A unipolar liquid activation apparatus as inclaim 1 wherein the means to electrically connect the first solutionelectrode and the second solution electrode is a wire between therespective cells.
 11. A unipolar liquid activation apparatus as in claim1 wherein the cathode and anode have a high surface area to increase thecontact area with the respective liquids.
 12. A method of sterilisationof liquid including the step of passing streams of the liquid throughrespective electrolytic cells, the electrolytic cells being an anodecell having an anode, a liquid inlet and an anolyte outlet and a cathodecell having an cathode, a liquid inlet and a catholyte outlet, a directcurrent power supply electrically connected to the anode and cathoderespectively, means to supply liquid to the anode and cathode cells, andmeans to recover the activated anolyte from the anode cell and theactivated catholyte from the cathode cell.